Strain-Induced Power Output Enhancement in Intrinsically Stretchable Organic Solar Cells

Abstract

Intrinsically stretchable organic solar cells (IS-OSCs) are a promising class of wearable power sources owing to their ability to stretch in multiple directions. Although the power conversion efficiency (PCE) and mechanical stretchability of IS-OSCs have significantly improved over the last 3–4 years, the current level of stretchability of IS-OSCs is not sufficient to meet the demands of wearable electronics. The power output (defined as PCE × photoactive area) of the OSCs is the most important figure-of-merit for determining the potential of these power sources. However, no effect on power output upon stretching has been reported from any type of solar cells. In this study, we construct highly stretchable and efficient photoactive systems by designing a new polymer donor (PBET-TF), which exhibits exceptional mechanical robustness (crack-onset strain (COS)= 80%). Consequently, PBET-TF-based IS-OSCs maintain over 80% of their original PCE up to 50% strain (strain at PCE80% = 50%), which significantly outperforms the reference PBDB-TF-based IS-OSCs (strain at PCE80%= 11%). Importantly, for the first time, we demonstrate strain-induced power output increases up to 50% strain in IS-OSCs using the developed PBET-TF-based photoactive systems. Therefore, this study showcases the concept of strain-induced power output enhancement in IS-OSCs, opening new research avenues and commercial possibilities for the IS-OSCs.

Keywords: intrinsically stretchable organic solar cells, polymer solar cells, mechanical robustness, stretchability, power output